It is common to make electrical boxes in various sizes to accommodate varying numbers and sizes of electrical components, such as electrical outlets, switches, etc. This multiplicity of sizes creates manufacturing and inventory problems for the fabricator, distributors, retailers and buildings.
There are two manners of construction concerned with electrical wall boxes. One is the "existing work" version in which a new electrical box is installed in existing construction, and the other manner is the "new work" construction in which a suitably sized electrical box is added to a structure in the process of being built. When an existing electrical box in existing construction must be expanded to hold, for example, two electrical switches, typically one must remove a large portion of the wall surrounding the existing electrical box. This greatly disfigures the area around the electrical box. After removing the existing electrical box, a differently-shaped, larger sized box is installed and wired after which the wall is refinished and repainted. This is a very labor-intensive and time-consuming task.
In "new work" construction where an electrical box is installed in a structure being built, an electrical box is typically connected to a support stud of the structure by means of a nail or screw attachment that is incorporated in the electrical box design. Drywall having holes cut for access to the electrical box is then installed to the support studs. Typically, in new construction, contractors must have on hand a multitude of differently sized electrical boxes to be able to select the required size as needed. Likewise, fabricators, distributors and retailers must be able to supply all of the sizes which may be required in any particular construction project.
Accordingly, it is desirable to have a single electrical box configuration that is easily gangable with an identical electrical box, hermaphroditic, and efficiently expandable in both existing and new work construction.